WO2018235462A1

WO2018235462A1 - Manufacturing method for image display device, and image display device obtained according to said manufacturing method

Info

Publication number: WO2018235462A1
Application number: PCT/JP2018/018846
Authority: WO
Inventors: 後藤　周作
Original assignee: 日東電工株式会社
Priority date: 2017-06-23
Filing date: 2018-05-16
Publication date: 2018-12-27
Also published as: CN110506307A; JP6770646B2; JPWO2018235462A1; TW201905508A; TWI708968B; KR102343171B1; CN110506307B; KR20200016198A

Abstract

Provided is a simple manufacturing method for a polarizing plate with a substrate, said polarizing plate being able to maintain superior optical characteristics even in a humidified environment, and preventing fading. This manufacturing method for a polarizing plate with a substrate includes: preparing a polarizing plate and a substrate of a larger size than the polarizing plate; layering the substrate and the polarizing plate, with the substrate extending from the periphery of the polarizing plate; forming a sealing section that covers a peripheral edge surface of the polarizing plate; and making the result a prescribed size by cutting the substrate and the sealing section, leaving an extension section of a prescribed length from the peripheral edge of the polarizing plate.

Description

Method of manufacturing image display device, and image display device obtained by the method

The present invention relates to a method of manufacturing an image display device and an image display device obtained by the method.

In an image display device (for example, a liquid crystal display device, an organic EL display device, or a quantum dot display device), a polarizing plate is often disposed on at least one side of a display cell due to the image forming method. There is. However, the polarizing plate has a problem of durability in that the optical properties of the polarizing film that substantially controls the optical properties of the polarizing plate are degraded in a humidified environment. More specifically, in the polarizing film, the polarization performance of the end portion is lost in a humidified environment, and as a result, a phenomenon of so-called color loss may occur in the image display device.

JP 2000-338329 A

The present invention has been made to solve the above problems, and its main object is to provide an image display device capable of maintaining excellent optical characteristics even in a humidified environment and in which color loss is prevented, and a simple manufacturing method thereof To provide.

According to the method of manufacturing an image display device of the present invention, a polarizing plate and a substrate having a size larger than the polarizing plate are prepared; the substrate extends from the outer periphery of the polarizing plate, and the substrate and the polarized light Laminating the plate; forming a sealing portion covering the peripheral end face of the polarizing plate; and leaving the substrate and the sealing portion leaving an extended portion of a predetermined length from the peripheral end of the polarizing plate Cutting and setting to a predetermined size.
In one embodiment, the substrate is a glass plate. In another embodiment, the substrate is a resin film.
In one embodiment, the manufacturing method laminates the substrate and the polarizing plate such that the substrate extends from all four sides of the outer periphery of the polarizing plate.
In one embodiment, the substrate is a display cell substrate of an image display device selected from a liquid crystal display device, an organic EL display device, and a quantum dot display device.
In one embodiment, the cutting is performed by irradiating a laser beam.
In one embodiment, the length of the extension portion of the sealing portion after the cutting is 10 μm to 500 μm.
In one embodiment, the moisture permeability of the sealing portion after the cutting is less than 300g ^/ m 2 ^/ 24hr.
According to another aspect of the present invention, an image display device is provided. The image display apparatus includes a polarizing plate, a substrate having an extending portion of a predetermined length from a peripheral end of the polarizing plate, and a sealing portion formed on the extending portion and covering the peripheral end face of the polarizing plate. Have.

According to the present invention, in the method of manufacturing an image display device, the sealing portion is formed on the portion of the substrate extending from the polarizing plate to seal the peripheral end face of the polarizing plate, and the sealing portion and the corresponding substrate are extended. By cutting the outgoing portion leaving a predetermined length from the peripheral edge of the polarizing plate, excellent optical characteristics can be maintained even in a humidified environment, and an image display device in which color loss is prevented can be easily manufactured. be able to.

FIG. 7 is a schematic view for explaining a method of manufacturing an image display device according to one embodiment of the present invention. It is a schematic diagram for demonstrating calculation of color loss amount. It is an image which shows the color-loss amount after the humidification test of the polarizing plate with a board | substrate as an image display apparatus alternative of Example 1. FIG. It is an image which shows the color-loss amount after the humidification test of the polarizing plate with a board | substrate as an image display apparatus alternative of the comparative example 1. FIG.

Hereinafter, although the embodiment of the present invention is described, the present invention is not limited to these embodiments.

A. Method of Manufacturing Image Display Device In the method of manufacturing an image display device of the present invention, a polarizing plate and a substrate having a size larger than the polarizing plate are prepared; the substrate is extended from the outer periphery of the polarizing plate Laminating the substrate and the polarizing plate; forming a sealing portion covering the peripheral end face of the polarizing plate; and leaving the extended portion of a predetermined length from the peripheral end of the polarizing plate. And cutting the seal to a predetermined size.

The present invention is applicable to any laminated structure of a substrate and a polarizing plate in an image display device. The substrate can be typically a display cell substrate of an image display device. As a representative example of the image display device, a liquid crystal display device, an organic EL display device, and a quantum dot display device can be mentioned. Examples of the display cell substrate include a substrate of a liquid crystal cell, a substrate of an organic EL cell, a substrate of a quantum dot display cell, and a substrate sealing a color filter from both sides in a liquid crystal display device. In one embodiment of the manufacturing method of the present invention, a substrate and a polarizing plate are laminated, and a sealing portion is formed on the laminated body to prepare a polarizing plate with a substrate, and the polarizing plate with a substrate is a display cell By using as a substrate, an image display device can be obtained. In another embodiment of the manufacturing method of the present invention, an image display device can be obtained by manufacturing a display cell, laminating a polarizing plate on a substrate of the display cell, and then forming a sealing portion. . Hereinafter, an embodiment using a polarizing plate with a substrate as a display cell substrate will be described as a representative example.

A-1. Preparation of Polarizer and Substrate First, as shown in FIG. 1A, the polarizer 10 and the substrate 20 are prepared. Hereinafter, the polarizing plate and the substrate will be specifically described.

A-1-1. Polarizing plate The polarizing plate has a polarizing film and a protective film disposed on at least one side of the polarizing film. In the embodiment of the present invention, the polarizing film is made of a polyvinyl alcohol resin (hereinafter referred to as "PVA resin") film containing iodine. When the polarizing film contains iodine, the effect of providing the sealing portion becomes remarkable. The thickness of the polarizing film is typically 8 μm or less. In the case where the polarizing film contains iodine and the thickness thereof is very thin as described above, the iodine density in the polarizing film becomes high, and the stability of iodine by humidification tends to decrease, so the sealing portion is provided. The effect is even more pronounced. The protective film may be disposed on one side or both sides of the polarizing film. When the protective film is disposed on one side of the polarizing film, it may be disposed on the display cell side or may be disposed on the opposite side of the display cell. Practically, a pressure-sensitive adhesive layer is provided as the outermost layer on the display cell side of the polarizing plate, and the polarizing plate is attached to the display cell via the pressure-sensitive adhesive layer. In addition, when it only says a protective film in this specification, it means a film (component of a polarizing plate) which protects such a polarizing film, and said surface protection film (film which protects a polarizing plate temporarily at the time of work) Is different from).

A-1-1-1. Polarizing Film As described above, the polarizing film is composed of a PVA-based resin film containing iodine. The polarizing film may be formed of a single-layer resin film, or may be formed of a laminate of two or more layers.

Specific examples of the polarizing film formed from a single layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) based films, partially formalized PVA based films, ethylene / vinyl acetate copolymer based partially saponified films, etc. In addition, those which have been subjected to a dyeing process and a drawing process with a dichroic substance such as iodine and a dichroic dye, and a polyene-based oriented film such as a dewatered product of PVA or a dehydrochlorinated product of polyvinyl chloride. Preferably, a polarizing film obtained by dyeing a PVA-based film with iodine and uniaxially stretching it is used because of excellent optical properties. The staining with iodine is performed, for example, by immersing a PVA-based film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. Stretching may be carried out after the dyeing process or may be carried out while dyeing. Moreover, it may be dyed after being drawn. If necessary, the PVA-based film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, and the like. For example, by immersing and washing the PVA-based film in water prior to dyeing, it is possible not only to wash the stains and anti-blocking agent on the surface of the PVA-based film, but also to swell the PVA-based film to make uneven dyeing It can be prevented.

As a specific example of the polarizing film obtained by using a laminate, a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a resin substrate and the resin The polarizing film obtained by using the laminated body with the PVA-type resin layer apply | coated-formed to the base material is mentioned. The polarizing film obtained by using a laminate of a resin substrate and a PVA-based resin layer applied and formed on the resin substrate is, for example, applying a PVA-based resin solution to the resin substrate and drying it. Forming a PVA-based resin layer thereon to obtain a laminate of a resin substrate and a PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer into a polarizing film; obtain. In the present embodiment, stretching typically includes dipping the laminate in a boric acid aqueous solution and stretching. Furthermore, stretching may optionally further comprise air-stretching the laminate at a high temperature (eg, 95 ° C. or higher) prior to stretching in an aqueous boric acid solution. The resulting laminate of resin substrate / polarizing film may be used as it is (that is, the resin substrate may be used as a protective film of polarizing film), and the resin substrate is peeled off from the laminate of resin substrate / polarizer. Alternatively, any appropriate protective film depending on the purpose may be laminated on the release surface. The details of the method for producing such a polarizing film are described, for example, in JP-A-2012-73580. The publication is incorporated herein by reference in its entirety.

Arbitrary suitable resin may be adopted as PVA system resin which forms the above-mentioned PVA system resin film. For example, polyvinyl alcohol and ethylene-vinyl alcohol copolymer can be mentioned. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of the PVA-based resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.9 mol%, more preferably 99.0 mol% to 99.5 mol%. . The degree of saponification can be determined according to JIS K 6726-1994. By using a PVA resin having such a degree of saponification, a polarizing film having excellent durability can be obtained. If the degree of saponification is too high, gelation may occur.

The average degree of polymerization of the PVA-based resin can be appropriately selected depending on the purpose. The average degree of polymerization is usually 1000 to 10000, preferably 1200 to 5000, and more preferably 1500 to 4500. The average degree of polymerization can be determined according to JIS K 6726-1994.

As mentioned above, the polarizing film contains iodine. The polarizing film is essentially a PVA-based resin film in which iodine is adsorbed and oriented. The iodine concentration in the PVA-based resin film is, for example, 5.0% by weight to 12.0% by weight. The boric acid concentration in the PVA-based resin film is, for example, 12% by weight to 25% by weight.

As described above, the thickness of the polarizing film is typically 8 μm or less, preferably 7 μm or less, and more preferably 6 μm or less. On the other hand, the thickness of the PVA-based resin film is preferably 1.0 μm or more, more preferably 2.0 μm or more.

The polarizing film preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizing film is preferably 40.0% to 46.0%, more preferably 41.0% to 45.0%. The polarization degree of the polarizing film is preferably 99.9% or more, more preferably 99.95% or more, and still more preferably 99.98% or more. When the polarizing plate is applied to a reflective liquid crystal display device or an organic EL display device, the polarization degree of the polarizing film is preferably 90% or more, more preferably 93% or more, and still more preferably 95%. It is above. As described later, such excellent optical characteristics (excellent balance between single transmittance and polarization degree) and excellent durability can be obtained by providing a sealing portion covering the peripheral end face of the image display panel including the polarizing film. It can be compatible with (being able to maintain such excellent optical characteristics even in a humidified environment).

A-1-1-2. Protective Film The protective film is composed of any suitable film that can be used as a protective film of a polarizing film. Specific examples of the material that is the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyether sulfone-based, and polysulfone-based Transparent resins such as polystyrenes, polynorbornenes, polyolefins, (meth) acrylics and acetates can be mentioned. In addition, thermosetting resins such as (meth) acrylic resins, urethane resins, (meth) acrylic urethane resins, epoxy resins, and silicone resins, ultraviolet curable resins, and the like can also be mentioned. Besides, for example, glassy polymers such as siloxane polymers can also be mentioned. Further, a polymer film described in JP-A-2001-343529 (WO 01/37007) can also be used. As a material of this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain, and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in a side chain For example, a resin composition having an alternating copolymer of isobutene and N-methyl maleimide and an acrylonitrile / styrene copolymer can be mentioned. The polymer film may be, for example, an extrusion of the resin composition.

In the embodiment of the present invention, as described above, the resin substrate used in the production of the polarizing plate may be used as it is as a protective film.

When the protective film is disposed on the visible side of the polarizing film in the polarizing plate disposed on the visible side, the protective film may be subjected to hard coating treatment, anti-reflection treatment, anti-sticking treatment, anti-glare treatment, etc. as necessary. Surface treatment may be applied.

As the thickness of the protective film, any appropriate thickness can be adopted as long as the effects of the present invention can be obtained. The thickness of the protective film is, for example, 10 μm to 40 μm, preferably 10 μm to 30 μm. In addition, when surface treatment is given, the thickness of a protective film is the thickness including the thickness of a surface treatment layer.

When a protective film (inner protective film) is disposed on the display cell side of the polarizing film, in one embodiment, the inner protective film is preferably optically isotropic. In the present specification, “optically isotropic” means that the in-plane retardation Re (550) is 0 nm to 10 nm, and the thickness direction retardation Rth (550) is −10 nm to +10 nm. Say. The Re (550) of the inner protective film is preferably 0 nm to 8 nm, more preferably 0 nm to 6 nm, and still more preferably 0 nm to 3 nm. The Rth (550) of the inner protective film is preferably -8 nm to +8 nm, more preferably -6 nm to +6 nm, and still more preferably -3 nm to +3 nm. In addition, "Re (550)" is an in-plane phase difference measured with the light of wavelength 550 nm in 23 degreeC. Re (550) is obtained by the formula: Re = (nx−ny) × d, where d (nm) is the thickness of the layer (film). “Rth (550)” is a retardation in the thickness direction measured with light having a wavelength of 550 nm at 23 ° C. Rth (λ) is obtained by the equation: Rth = (nx−nz) × d, where d (nm) is the thickness of the layer (film).

In another embodiment, the inner protective film may have Re (550) that can function as a so-called λ / 4 plate. Such an embodiment can be applied, for example, when the polarizing plate functions as a circularly polarizing plate and is used as an antireflection film of a reflective liquid crystal display device or an organic EL display device. In this case, Re (550) is preferably 120 nm to 160 nm, more preferably about 140 nm. In this case, the inner protective film may be arranged such that its slow axis is preferably at an angle of 40 ° to 50 °, more preferably about 45 °, to the absorption axis of the polarizing film.

A-1-2. Substrate Any appropriate configuration may be employed as the substrate. For example, the substrate may be a glass plate or a resin film. The substrate has a larger size than the polarizer. The substrate preferably has a size that extends a predetermined length from the outer periphery of the polarizing plate when laminated with the polarizing plate, and more preferably a predetermined length from all four sides forming the outer periphery of the polarizing plate It has an extending size.

Any appropriate glass plate may be employed as the glass plate. Examples of the glass constituting the glass plate include soda lime glass, borate glass, aluminosilicate glass and quartz glass according to the classification according to the composition. Moreover, according to the classification by an alkali component, non-alkali glass and low alkali glass are mentioned. The content of the alkali metal component (eg, Na ₂ O, K ₂ O, Li ₂ O) of the glass is preferably 15% by weight or less, more preferably 10% by weight or less.

The light transmittance at a wavelength of 550 nm of the glass plate is preferably 85% or more. The refractive index of the glass plate at a wavelength of 550 nm is preferably 1.4 to 1.65. The density of the glass plate is preferably 2.3 g / cm ³ to 3.0 g / cm ³ , more preferably 2.3 g / cm ³ to 2.7 g / cm ³ .

The thickness of the glass plate is preferably 0.1 mm to 1.0 mm, more preferably 0.2 mm to 0.6 mm.

As the glass plate, a commercially available glass plate may be used as it is, or a commercially available glass plate may be used after being polished to a desired thickness. Examples of commercially available glass plates include "7059", "1737" or "EAGLE 2000" manufactured by Corning, "AN 100" manufactured by Asahi Glass, "NA-35" manufactured by NH Techno Glass, "OA- manufactured by Nippon Electric Glass Co., Ltd." 10 "," D263 "or" AF 45 "manufactured by Schott AG.

Any appropriate resin film may be employed as the resin film. The resin film is typically a transparent resin film. As a material which comprises a resin film, a polyimide and a polyamide imide are mentioned, for example. These may be used alone or in combination.

The thickness of the resin film is preferably 10 μm to 200 μm, and more preferably 20 μm to 100 μm.

A-2. Lamination of Polarizing Plate and Substrate Next, as shown in FIG. 1A, the polarizing plate 10 and the substrate 20 are laminated. The polarizing plate 10 and the substrate 20 can typically be laminated via any appropriate pressure-sensitive adhesive layer (not shown). The lamination is performed in such a manner that the substrate extends from the outer periphery of the polarizing plate as shown in FIG. 1A, and preferably, the substrate extends from all four sides constituting the outer periphery of the polarizing plate It will be.

If necessary, a surface protective film (not shown) may be temporarily attached to the surface of the polarizing plate 10 opposite to the substrate 20. Thereby, in formation of the below-mentioned sealing part, and cutting of the sealing part concerned and a substrate, a polarizing plate may be protected appropriately. The surface protective film is peeled off at the final use of the polarizing plate with substrate (substantially, the image display device). Peeling removal of the surface protective film may be performed at any suitable timing after formation of the sealing portion and cutting of the sealing portion and the substrate.

A-3. Formation of Sealed Portion Next, as shown in FIG. 1B, a sealed portion 30 covering the peripheral end face of the polarizing plate 10 is formed. By covering the peripheral end face of the polarizing plate with the sealing portion, the optical characteristics of the polarizing plate (polarizing film) can be maintained even in a humidified environment, and as a result, the durability of the image display device can be improved. Therefore, the sealing portion preferably has a barrier function. As used herein, “having a barrier function” means controlling the amount of transmission of oxygen and / or water vapor entering the polarizing film to substantially block the polarizing film from them.

The sealing portion is typically formed by arranging the pressure-sensitive adhesive composition so as to cover the peripheral end face of the polarizing plate. In one embodiment, the sealing portion may be formed by disposing (for example, applying, disposing a sheet-like pressure-sensitive adhesive) the pressure-sensitive adhesive composition to the extended portion of the substrate. The sealing portion covers the peripheral end face of the polarizing plate, as long as the peripheral end face is sealed, and does not have to be in close contact with the peripheral end face. Further, the sealing portion may cover the peripheral end face of the polarizing plate, and therefore may cover the peripheral end face and a portion other than the peripheral end face. For example, the sealing portion may cover a surface (upper surface in the drawing) of the polarizing plate on the side away from the substrate together with the peripheral end face. In this case, the surface may be entirely covered, or only a predetermined portion may be covered.

The pressure-sensitive adhesive composition includes, for example, a rubber-based pressure-sensitive adhesive composition containing a rubber-based polymer as a base polymer.

As a rubber-based polymer, for example, a conjugated diene-based polymer obtained by polymerizing one kind of conjugated diene compound, a conjugated diene-based copolymer obtained by polymerizing two or more kinds of conjugated diene compounds, a conjugated diene The conjugated diene type copolymer obtained by copolymerizing a compound and an aromatic vinyl compound, and these hydrogenated substances are mentioned.

The conjugated diene compound is not particularly limited as long as it is a monomer having a polymerizable conjugated diene. Specific examples of conjugated diene compounds are 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene And 1,3-hexadiene. Among these, 1,3-butadiene and isoprene are preferable from the viewpoint of industrial availability. The conjugated diene compounds may be used alone or in combination.

The aromatic vinyl compound is not particularly limited as long as it is a monomer having an aromatic vinyl structure copolymerizable with the conjugated diene compound. Specific examples of the aromatic vinyl compound include styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene and the like. Among these, styrene is preferable from the viewpoint of industrial availability. The aromatic vinyl compounds may be used alone or in combination.

The diene copolymer may be a random copolymer or a block copolymer. Further, a diene copolymer may be obtained by copolymerizing a compound other than a conjugated diene compound and an aromatic vinyl compound.

The conjugated diene copolymer obtained by copolymerizing the conjugated diene compound and the aromatic vinyl compound has a molar ratio of the conjugated diene compound to the aromatic vinyl compound of conjugated diene compound / aromatic vinyl compound = 10/90. It is preferable to be -90/10 (mol%).

Specific examples of such conjugated diene-based (co) polymers include butadiene rubber (BR), isoprene rubber (IR), styrene-butadiene copolymer (SBR), butadiene-isoprene-styrene random copolymer, isoprene Styrene random copolymers, styrene-isoprene block copolymers (SIS), butadiene-styrene copolymers, styrene-ethylene-butadiene block copolymers (SEBS), acrylonitrile-butadiene rubbers (NBR). These may be used alone or in combination. Among these, isoprene-styrene copolymer is preferable. Moreover, these hydrogenated substances can also be used suitably.

As a rubber-based polymer, in addition to conjugated diene (co) polymers, isobutylene (IB), styrene-isobutylene-styrene block copolymer (SIBS), styrene-ethylene-propylene copolymer-styrene block copolymer, etc. Can also be used. The rubber-based polymers may be used alone or in combination.

The rubber-based polymer that can be used in the present invention is preferably 50% by weight or more, more preferably 70% by weight or more, and still more preferably 80% by weight or more of the conjugated diene-based (co) polymer in the entire rubber-based polymer. Particularly preferably, it contains 90% by weight or more. The upper limit of the content of the conjugated diene-based (co) polymer is not particularly limited, and may be 100% by weight (that is, a rubber-based polymer consisting only of the conjugated diene-based (co) polymer).

As mentioned above, the pressure-sensitive adhesive composition contains a rubber-based polymer as a base polymer. The content of the rubber-based polymer in the pressure-sensitive adhesive composition is preferably 40% by weight or more, more preferably 50% by weight or more, and still more preferably 60% by weight or more. The upper limit of the content of the rubber-based polymer is not particularly limited, and is, for example, 90% by weight or less.

The pressure-sensitive adhesive composition may further contain any appropriate additive in addition to the rubber-based polymer. Specific examples of the additive include a crosslinking agent (eg, polyisocyanate, epoxy compound, alkyl etherified melamine compound, etc.), a tackifier (eg, rosin derivative resin, polyterpene resin, petroleum resin, oil-soluble phenol resin, vinyl toluene) And the like), plasticizers, fillers (eg, layered silicates, clay materials, etc.), anti-aging agents. The type, combination, addition amount and the like of the additive added to the pressure-sensitive adhesive composition may be appropriately set depending on the purpose. The content (total amount) of the additive in the pressure-sensitive adhesive composition is preferably 60% by weight or less, more preferably 50% by weight or less, and still more preferably 40% by weight or less.

The thickness of the sealing portion 30 thus formed is preferably 30 μm to 1000 μm, more preferably 50 μm to 500 μm. In the present specification, “the thickness of the sealing portion” is the thickness in the direction extending outward from the peripheral end face of the polarizing plate unless stated otherwise (ie, the thickness of the sealing portion is the length of the extended portion of the substrate Correspond to the

A-4. Next, as shown in FIG. 1C, the sealing portion 30 and the substrate 20 are cut leaving an extended portion of a predetermined length from the peripheral edge of the polarizing plate. As a result, as shown in FIG. 1D, a sealing portion 40 having a predetermined thickness is formed. The thickness of the sealing portion 40 after cutting is preferably 10 μm to 500 μm, and more preferably 20 μm to 300 μm.

The cutting may be performed mechanically or by laser light irradiation.

Mechanical cutting includes milling and end milling.

The laser light preferably comprises light of a wavelength of at least 1500 nm or less. The laser light more preferably includes light of a wavelength of 100 pm to 1000 nm, further preferably light of a wavelength of 400 nm to 900 nm, and particularly preferably light of a wavelength of 420 nm to 680 nm. In one embodiment, the laser light has a peak wavelength in the range as described above. According to the laser beam containing such a wavelength, it can cut | disconnect favorably over the thickness direction of the upper and lower sides of a sealing part.

Examples of the laser include solid lasers such as YAG lasers, YLF lasers, YVO4 lasers, and titanium sapphire lasers, gas lasers including argon ion lasers, krypton ion lasers, fiber lasers, semiconductor lasers, and dye lasers. Preferably, a solid state laser is used.

As the laser, preferably, a short pulse laser (a laser that emits light having a pulse width of 1 nanosecond or less, for example, a picosecond laser or a femtosecond laser) is used. A pulse width of 500 picoseconds or less (for example, 10 picoseconds to 50 picoseconds) is particularly preferable for the purpose of suppressing heat damage to the sealing portion. By suppressing the heat damage, a beautiful, uniform and smooth cut surface can be obtained.

The irradiation conditions of the laser light may be set to any appropriate conditions. For example, when using a solid state laser (YVO4 laser), the pulse energy is preferably 10 μJ to 150 μJ, more preferably 25 μJ to 71 μJ. The scan speed is preferably 10 mm / sec to 10000 mm / sec, more preferably 100 mm / sec to 1000 mm / sec. The repetition frequency is, for example, 100 Hz to 12480 Hz. The scan pitch is preferably 10 μm to 50 μm. The beam shape at the irradiation position of the laser beam can be appropriately set according to the purpose. The beam shape may be, for example, circular or linear. Any appropriate means may be employed as a means for making the beam shape into a predetermined shape. For example, laser irradiation may be performed through a mask having a predetermined opening, or beam shaping may be performed using a diffractive optical element or the like. For example, when the beam shape is circular, the focal diameter (spot diameter) is preferably 50 μm to 60 μm. Furthermore, the input energy of the pulse laser is preferably 20000 μJ / mm ² to 100000 μJ / mm ² , more preferably 25000 μJ / mm ² to 75000 μJ / mm ² . The input energy E (μJ / mm ² ) can be obtained from the following equation.
E = (e × M) / (V × p)
e: Pulse energy (J)
M: Repetition frequency (Hz)
V: Scan speed (mm / sec)
p: Scan pitch (mm)

The irradiation mode (scanning mode) of the laser beam can be appropriately set according to the purpose. For example, the laser light may be scanned linearly, may be scanned S-shaped, may be scanned spirally, or may be combined.

The sealing portion 40 formed as described above has a barrier property, and typically has a barrier property against moisture and gas (for example, oxygen). 40 ° C. of the sealing portion 40, the water vapor transmission rate at 90% RH conditions (moisture permeability) is preferably not more than 300g ^/ m 2 ^/ 24hr, more preferably at most 100g ^/ m 2 ^/ 24hr, further preferably not more than ^50g / m 2 / 24hr, most preferably not more than ^25g / m 2 / 24hr. The lower limit of the moisture permeability, for example, 0.01g ^/ m 2 ^/ 24hr, and preferably below the detection limit. If the moisture permeability of the sealing portion 40 is in such a range, the image display panel can be well protected from moisture and oxygen in the air. The moisture permeability can be measured in accordance with JIS Z0208.

As described above, as shown in FIG. 1D, the substrate-attached polarizing plate 100 having a predetermined size can be manufactured.

A-5. Production of Image Display Device In the present embodiment, an image display device can be obtained by using the polarizing plate with substrate obtained as described above as a display cell substrate. When manufacturing a liquid crystal display device, the following procedures can be employed as an example: (1) preparing a pair of polarizing plates with a substrate; (2) on the substrate surface of one polarizing plate with a substrate A switching element (for example, TFT) is provided, and a color filter is provided on the substrate surface of the other polarizing plate with substrate; (3) an alignment film is formed on each substrate surface; 2.) The substrates are attached to each other with the substrates facing each other (with the polarizers disposed on the outer side), with the spacers interposed therebetween; (5) the liquid crystal is sealed between the substrates. In this way, an image display can be produced.

A-6. Other Embodiments Although the embodiment using the polarizing plate with substrate as the display cell substrate has been described above, as described above, the manufacturing method of the present invention produces a display cell and uses the polarizing plate on the substrate of the display cell. An image display apparatus can be obtained by laminating and then forming a sealing portion. In the present embodiment, the following procedure can be adopted as an example:
(A-1) preparing a pair of substrates; (a-2) providing a switching element (for example, TFT) on the surface of one of the substrates and providing a color filter on the surface of the other substrate; (a-3) each of the substrates An alignment film is formed on the surface and alignment processing is performed on the alignment film; (a-4) bonding substrates through spacers; (a-5) sealing a liquid crystal between the substrates to produce a display cell;
(B) The display cell extends from the outer periphery of the polarizing plate (preferably, the display cell extends from all four sides of the outer periphery of the polarizing plate) Laminating a polarizing plate on the outside;
(C) forming a sealing portion covering the peripheral end face of the polarizing plate;
(D) The sealing portion and the peripheral portion of the display cell are cut leaving an extending portion of a predetermined length from the peripheral edge of the polarizing plate.
In this way, an image display can be produced. The details of the steps (b) to (d) are as described in the above section A-2 to A-4. In addition, in the peripheral portion of the display cell, a cutting margin is secured so as not to adversely affect cutting.

It is obvious to those skilled in the art that the present invention can be applied to any laminated structure of a substrate and a polarizing plate in an image display device other than the embodiments described above. If this specification is read, those skilled in the art can laminate the substrate and the polarizing plate, form the sealing portion, and cut the sealing portion and the substrate into any laminated structure of the substrate and the polarizing plate in the image display device. It can be applied to

B. Image Display Device The image display device of the present invention is obtained by the manufacturing method described in the above section A. Therefore, the image display device typically includes a structure as shown in FIG. 1 (d). Specifically, the image display device includes a polarizing plate, a substrate having an extending portion having a predetermined length from a peripheral end of the polarizing plate, and a seal formed on the extending portion and covering the peripheral end face of the polarizing plate Part.

The image display device preferably has a color loss of 100 μm or less, more preferably 50 μm or less, and still more preferably 30 μm or less, after holding for 120 hours in an environment of 85 ° C. and 85% RH. Is 25 μm or less. The lower limit of the amount of color loss is preferably zero, and in one embodiment 5 μm. The amount of color loss is determined by leaving an image display device substitute (substantially, a polarizing plate with a substrate) in an oven at 85 ° C. and 85% RH for 120 hours to humidify, and then in a state of cross polarizer with a standard polarizing plate. When placed, the state of color loss at the end is examined with a microscope. Specifically, the size of the color loss (color loss amount: μm) from the end of the polarizing plate or the polarizing film is measured. As shown in FIG. 2, the larger one of the color loss amount a from the end in the stretching direction and the color loss amount b from the edge in the direction orthogonal to the stretching direction is taken as the color loss amount. In addition, the area | region which lose | eliminated the color has the polarization characteristic very low, and does not function as a polarizing plate substantially. Therefore, the smaller the color loss amount, the better.

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. In addition, the measuring method of each characteristic is as follows.

(1) Thickness The thickness was measured using a digital micrometer (KC-351C manufactured by Anritsu Corporation).
(2) Moisture Permeability Using the pressure-sensitive adhesive composition prepared in Examples and Comparative Examples, a pressure-sensitive adhesive sheet having the structure of release liner / pressure-sensitive adhesive layer (having a thickness of Example or Comparative Example) / release liner was formed. . The release liner on one side of the adhesive sheet is peeled off to expose the adhesive surface, and the adhesive sheet is bonded to a triacetylcellulose film (TAC film, 25 μm thick, Konica Minolta Co., Ltd.) through the adhesive surface, 10 cmφ It cut out in the shape of a circle. Finally, the other release liner was peeled off to obtain a measurement sample. The moisture permeability (water vapor permeability) of the obtained measurement sample was measured by the moisture permeability test method (cup method, in accordance with JIS Z 0208). The measurement conditions were as follows. In addition, a constant temperature and humidity chamber was used at the time of measurement.
Measurement temperature: 40 ° C
Relative humidity: 92%
Measurement time: 24 hours (3) Decoloration amount After polarizing plates with a substrate obtained in Examples and Comparative Examples after leaving for 120 hours in an oven at 85 ° C. and 85% RH as an image display device alternative, The state of loss of color at the end of the polarizing film when placed in the state of cross nicol with the standard polarizing plate was examined by a microscope. Specifically, the size (color loss amount: μm) of color loss from the end of the polarizing film was measured. The amount of color loss was measured from an image taken at a magnification of 10 × using an Olympus MX61L as a microscope. As shown in FIG. 2, the larger one of the color loss amount a from the end in the stretching direction and the color loss amount b from the edge in the direction orthogonal to the stretching direction is taken as the color loss amount.

Example 1
As a resin substrate, an amorphous polyethylene terephthalate (IPA copolymerized PET) film having a thickness of 100 μm and 7 mol% of an isophthalic acid unit having a Tg of 75 ° C. was prepared. The surface of this film was subjected to corona treatment (55 W / m ² / min).
Acetoacetyl-modified PVA (manufactured by Japan Synthetic Chemical Industry Co., Ltd., trade name: Gosefamer (registered trademark) Z200) and PVA (average degree of polymerization: 4200, degree of saponification: 99.2 mol%): 1: 9 A PVA-based resin was prepared, and 13 parts by weight of potassium iodide was added to 100 parts by weight of the PVA-based resin to prepare a PVA-based resin aqueous solution (PVA-based resin concentration: 5.5% by weight). This aqueous solution is applied to the corona-treated surface of the resin substrate so that the film thickness after drying is 13 μm, dried by hot air drying in an atmosphere of 60 ° C. for 10 minutes, and a 9 μm-thick PVA-based resin A resin layer was formed. Thus, a laminate was produced.
The obtained laminate was stretched 2.4 times at 120 ° C. in air (air-assisted stretching).
Then, the laminate was immersed in a boric acid aqueous solution having a liquid temperature of 40 ° C. for 30 seconds to insolubilize the PVA-based resin layer. The boric acid aqueous solution in this step had a boric acid content of 4 parts by weight with respect to 100 parts by weight of water.
Next, the laminate was dipped and dyed in a staining solution containing iodine and potassium iodide at a liquid temperature of 30 ° C. for an arbitrary time such that the single transmittance of the obtained polarizing film was about 42 to 45%. The staining solution contains water as a solvent, an iodine concentration of 0.1 to 0.4% by weight, a potassium iodide concentration of 0.7 to 2.8% by weight, iodine and potassium iodide. The ratio of concentrations of is 1: 7.
Then, the laminate was immersed in a 40 ° C. aqueous boric acid solution for 60 seconds to crosslink the PVA resin layer to which iodine was adsorbed. In the boric acid aqueous solution of this step, the boric acid content was 5 parts by weight with respect to 100 parts by weight of water, and the potassium iodide content was 3 parts by weight with respect to 100 parts by weight of water.
Furthermore, the laminate was stretched in an aqueous solution of boric acid at a stretching temperature of 70 ° C. and stretched 2.3 times in the same direction as the above-described air-assisted supplemental stretching (final stretch ratio 5.50 times). The boric acid aqueous solution in this step had a boric acid content of 3.5 parts by weight with respect to 100 parts by weight of water, and a potassium iodide content of 5 parts by weight with respect to 100 parts by weight of water.
Next, the laminate is washed with an aqueous solution having a potassium iodide content of 4 parts by weight with respect to 100 parts by weight of water, and dried with warm air at 60 ° C. to obtain a polarizing film with a thickness of 5 μm The

A cycloolefin film (manufactured by Nippon Zeon Co., Ltd., ZF-12, 23 μm) was bonded to the surface of the obtained polarizing film (surface on the side opposite to the resin substrate) via a UV-curable adhesive. Specifically, a UV curable adhesive was applied to each of the polarizing film and the cycloolefin film so as to have a total thickness of 1.0 μm, and the films were pasted together using a roll machine. Thereafter, ultraviolet rays were irradiated from the side of the cycloolefin film to cure the curable adhesive. Next, the resin base material is peeled off, and a λ / 4 plate of cycloolefin based film (made by Nippon Zeon Co., Ltd., ZD-12, thickness 23 μm, Re (550) = 140 nm) via the curable adhesive on the peeled surface. To obtain a polarizing plate having a structure of cycloolefin film ZD-12 (protective film) / polarizing film / cycloolefin film ZF-12 (protective film). The ZD-12 film was bonded such that its slow axis made an angle of 45 ° with the absorption axis of the polarizing film. This polarizing plate can be used, for example, as a viewing side polarizing plate (antireflection film) of a reflective liquid crystal display device or an organic EL display device.

The polarizing plate obtained above was cut into a 90 mm × 40 mm size so that the absorption axis direction of the polarizing film was the long side direction. On the other hand, a commercially available glass plate (manufactured by Matsunami Glass Co., Ltd., thickness 0.4 mm) was cut out to a size of 110 mm × 60 mm as a substrate. The cut out polarizing plate and the cut out substrate were laminated via an acrylic pressure-sensitive adhesive. Here, the polarizing plate and the substrate were laminated such that the ZD-12 film (λ / 4 plate) of the polarizing plate was disposed on the substrate side. The polarizing plate and the substrate were laminated such that the substrate extended from all four sides constituting the outer periphery of the polarizing plate. The lengths of the four extended portions of the substrate were 10 mm each.

An adhesive was placed in the above-mentioned extended portion, and the peripheral end face of the polarizing plate was sealed. Thus, the sealing part which covers the peripheral end face of a polarizing plate was formed. The pressure-sensitive adhesive constituting the sealing portion is 100 parts by weight of a styrene / ethylene propylene copolymer / styrene block copolymer (manufactured by Kuraray Co., Ltd., trade name "Septon 2063", styrene content: 13% by weight) 10 parts by weight of polybutene (manufactured by JX Nippon Mining & Energy Co., Ltd., “trade name“ Niseki polybutene HV-300 ””, 40 parts by weight of terpene phenol tackifier (trade name “YS Polystar TH130” manufactured by Yashara Chemical Co., Ltd.), and aroma Group tackifier (manufactured by Eastman Chemical Co., Ltd., trade name "Picolastic A5").

Next, the adhesive and the substrate were irradiated with a laser beam, and the adhesive was cut so as to leave 100 μm from the peripheral edge of the polarizing plate, to form a final sealing portion. The moisture permeability of the resulting sealing portion was ^12g / m 2 / 24hr. The irradiation of the laser light was performed using "LaserPro Spirit" manufactured by GCC.

As described above, a polarizing plate with a substrate was produced. The obtained polarizing plate with a substrate was subjected to the evaluation of the color loss described in the above (3). The results are shown in Table 1. Furthermore, the state of color loss is shown in FIG.

Example 2
A cycloolefin film (Nippon Zeon Co., Ltd., ZF-12, 13 μm) is affixed to the polarizing film surface of the resin base material / polarizing film laminate obtained in the same manner as in Example 1 in the same manner as in Example 1. I put it together. Next, the resin base material is peeled off, and a reflective polarizer (APF-V3 manufactured by 3M) is attached to the peeled surface via an adhesive (12 μm), and a cycloolefin film ZF-12 (protective film) A polarizing plate having a structure of: polarizing film / reflection type polarizer was obtained. The reflective polarizer was bonded such that its transmission axis and the transmission axis of the polarizing film formed an angle of 0 °. This polarizing plate can be used, for example, as a back side polarizing plate.

The following procedure was performed in the same manner as in Example 1 to prepare a polarizing plate with a substrate. The polarizing plate and the substrate were laminated such that the ZF-12 film (protective film) of the polarizing plate was disposed on the substrate side. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 3]
A cycloolefin film (Nippon Zeon Co., Ltd., ZF-12, 13 μm) is affixed to the polarizing film surface of the resin base material / polarizing film laminate obtained in the same manner as in Example 1 in the same manner as in Example 1. I put it together. Then, the resin substrate was peeled off to obtain a polarizing plate having a structure of cycloolefin film ZF-12 (protective film) / polarizing film. The following procedure was performed in the same manner as in Example 1 to prepare a polarizing plate with a substrate. The polarizing plate and the substrate were laminated such that the polarizing film was disposed on the substrate side. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

Example 4
Moisture permeability was produced 24g ^/ m 2 / 24hr sealing portion is except for (having a thickness of 50 [mu] m) in the same manner as in Example 1 polarizing plate with the substrate. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 5]
Moisture permeability was produced 24 g / m ^2/24 hr or sealing portion which is except for (having a thickness of 50 [mu] m) in the same manner as in Example 2 polarizer with substrate. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 6]
Moisture permeability was produced 24g ^/ m 2 / 24hr sealing portion is except for (having a thickness of 50 [mu] m) in the same manner as in Example 3 polarizing plate with the substrate. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

Comparative Example 1
A polarizing plate with a substrate was produced in the same manner as in Example 1 except that the sealing portion was not formed. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1. Furthermore, the state of color loss is shown in FIG.

Comparative Example 2
Sealing portion except for using an ordinary acrylic adhesive in the same manner as in Example 1 (moisture permeability: greater than 1000g ^/ m 2 / 24hr, thickness: 25 [mu] m) was formed, a polarizing plate was prepared with substrate . The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

As apparent from Table 1, by forming a sealing portion having a predetermined moisture permeability on the outer peripheral end face of the polarizing plate, a polarizing plate with a substrate capable of maintaining excellent optical characteristics even in a humidified environment (finally , Image display device) can be obtained.

The image display device obtained by the manufacturing method of the present invention includes a television, a display, a mobile phone, a portable information terminal, a digital camera, a video camera, a portable game machine, a car navigation system, a copier, a printer, a fax machine, a watch, a microwave, etc. It is preferably used.

10 Polarizing plate 20 Substrate 30 Sealing portion 40 Sealing portion (final)
100 Polarizing plate with substrate

Claims

Preparing a polarizing plate and a substrate having a size larger than the polarizing plate;
Laminating the substrate and the polarizing plate such that the substrate extends from the outer periphery of the polarizing plate;
Forming a sealing portion covering the peripheral end face of the polarizing plate, and cutting the substrate and the sealing portion leaving a portion extending a predetermined length from the peripheral end of the polarizing plate to a predetermined size And a method of manufacturing an image display device.
The method according to claim 1, wherein the substrate is a glass plate.
The method according to claim 1, wherein the substrate is a resin film.
The manufacturing method according to any one of claims 1 to 3, wherein the substrate and the polarizing plate are laminated such that the substrate extends from all four sides forming the outer periphery of the polarizing plate.
The manufacturing method according to any one of claims 1 to 4, wherein the substrate is a display cell substrate of an image display device selected from a liquid crystal display device, an organic EL display device and a quantum dot display device.
The manufacturing method according to any one of claims 1 to 5, wherein the cutting is performed by irradiating a laser beam.
The manufacturing method according to any one of claims 1 to 6, wherein a length of an extension portion of the sealing portion after the cutting is 10 μm to 500 μm.
The moisture permeability of the sealing portion after cutting is not more than 300g / m 2 / 24hr, the manufacturing method according to any one of claims 1 to 7.
An image display device comprising: a polarizing plate; a substrate having an extending portion of a predetermined length from a peripheral end of the polarizing plate; and a sealing portion formed on the extending portion and covering the peripheral end face of the polarizing plate.